Pretreatment agents for acidic hair dyes

ABSTRACT

Pretreatment agents for hair colorings with acid dye comprising at least one cationic polymer selected from the group consisting of polymers having amino groups and polymers having quaternary ammonium groups. The pretreatment agents for hair colorings with acid dye are used for improving coloring ability and color fastness of hair colorings with acid dye.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/JP01/06033 which has an Internationalfiling date of Jul. 12, 2001, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a pretreatment agent for a haircoloring with acid dye. More specifically, the present invention relatesto a pretreatment agent for a hair coloring with acid dye, whichimproves coloring ability and color fastness of the hair coloring withacid dye.

BACKGROUND ART

A hair coloring with acid dye has a defect such that the coloringability is generally weaker than an oxidation hair dye. Therefore, inorder to eliminate the defects, various attempts hitherto have beenstudied.

As a process for improving coloring ability, there has been known amethod of adding benzyl alcohol, 2-benzyloxyethanol, urea, phenol,m-cresol or the like to an acidic water bath containing acid dye or thelike, used in a solvent-assisted dyeing or a low-temperature dyeing inthe case of wool dyeing (“Senyoku no Kiso Butsurikagaku,” authored byMitsuo Kimura, Sennikenkyusha, p. 51–54). Among the above-mentionedcomponents added, benzyl alcohol has been generally widely used as apenetration agent for the acid dye. However, when this method is appliedto a hair coloring with acid dye, there are some defects in this processsuch that coloring ability and color fastness of the hair coloring withacid dye become worse than those of the oxidation hair dye.

Also, as another process for improving coloring ability, there has beenproposed to use 2-benzyloxyethanol (Japanese Patent Laid-Open No. Hei4-69323). However, there are some defects in this process such thatcoloring ability and color fastness are equivalent to or lower thanthose of the above-mentioned benzyl alcohol.

Also, as one of low-temperature dyeing processes of keratin fibers suchas wool or human hair, there have been proposed a process comprisingpreviously treating keratin fibers with an amphoteric surfactant, andthereafter dyeing the keratin fibers (Japanese Patent Laid-Open No. Hei2-502740); the above process using a cationic surfactant in place of theamphoteric surfactant (Japanese Patent Laid-Open No. Hei 8-301738); andthe like. However, there are some defects in these processes such thatcoloring ability is not improved, and that coloring ability especiallyfor damaged hair is rather worsened when combined with a commerciallyavailable hair coloring with acid dye.

Incidentally, as a component for improving luster, smooth combing,feeling and the like, there has been proposed to use cationic polymers.Among them, since polyethyleneimine is alkaline, there have beenproposed to use the polyethyleneimine in a hair color containing an aciddye in place of an alkalizing agent such as ammonia or monoethanolamine(Japanese Examined Patent Publication No. Hei 6-13451); a hair dyecomposed of a first agent comprising polyethyleneimine and a secondagent comprising a melanine precursor such as tyrosine or DL-β-alanineand a metal salt (Japanese Examined Patent Publication No. Sho61-20523); and the like.

The cationic polymer has been used not only as an agent for improvingluster, smooth combing and feeling as described above, but also as adyeing assistance for improving coloring ability. However, there has notyet been reported a case where a cationic polymer is employed in aciddye.

As the reasons therefor, there can be cited that the acidic dye has asulfo group in the molecule, so that an ion complex is formed betweenthe sulfo group of acid dye and cationic group when the cationic polymerexists in acid dye, whereby the acid dye cannot be efficientlypenetrated into the human hair, and therefore an alkaline cationicpolymer such as polyethyleneimine cannot be mixed with acid dye.

From these reasons, it has been hitherto thought that simultaneous useof the cationic polymer and acid dye would be difficult.

DISCLOSURE OF INVENTION

In view of the above-mentioned prior art, an object of the presentinvention is to provide a means for further improving coloring abilityand color fastness of a hair coloring with acid dye.

Another object of this invention is to provide a pretreatment agent fora hair dye, which is excellent not only in decoloring ability but alsoin coloring ability and color fastness when dyed with a hair coloringwith acid dye after removing dye from colored hair, which gives nosqueakiness during rinsing, and adequately keeps hair feeling.

According to this invention, there is provided a pretreatment agent fora hair coloring with acid dye comprising at least one cationic polymerselected from the group consisting of a polymer having amino groups anda polymer having quaternary ammonium groups.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Example 21 of this invention.

FIG. 2 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Example 22 of this invention.

FIG. 3 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Example 23 of this invention.

FIG. 4 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Example 24 of this invention.

FIG. 5 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Comparative Example 5.

FIG. 6 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Comparative Example 6.

FIG. 7 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Example 25 of this invention.

FIG. 8 is a cross-sectional microphotograph (magnification: 400) ofcolored hair obtained in Example 26 of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION

As described above, the pretreatment agent for a hair coloring with aciddye of this invention contains at least one cationic polymer selectedfrom the group consisting of a polymer having amino groups and a polymerhaving quaternary ammonium groups.

Since a specific cationic polymer is contained in the pretreatment agentfor a hair coloring with acid dye of this invention as mentioned above,cation is introduced into hair when hair is treated with thepretreatment agent before coloring the hair with a hair coloring withacid dye. Therefore, there are exhibited excellent effects such that notonly coloring ability and color fastness of a hair coloring with aciddye are improved, but also squeakiness is reduced when rinsing hair.Also, the same excellent effects as mentioned above are exhibited notonly for virgin hair but also for damaged hair.

The polymer having amino groups includes, for instance, primary aminepolymers such as polyacrylamide, polyvinylamine, polyethyleneimine(hereinafter referred to as PEI) and their derivatives; secondary aminepolymers such as polyamine, PEI and their derivatives; tertiary aminepolymers such as PEI and their derivatives; and the like. These cationicpolymers can be used alone or in admixture of at least two kinds. SincePEI and its derivatives have a primary amino group, a secondary aminogroup and a tertiary amino group, they can be used as any one of primaryamine polymer, secondary amine polymer and tertiary amine polymer.

Among these polymers having amino groups, PEI and its derivatives have ahigh density of electric charges and many cation charges in themolecule, PEI and its derivatives can be suitably used.

The derivative of PEI includes, for instance, a PEI derivative in whichpolyoxyethylene, polyoxypropylene, polyoxybutylene or an alkyl grouphaving a molecular chain of 4 to 22 carbon atoms is added to secondaryamino group or tertiary ethyleneimino group of PEI in an amount ofequimolar or greater.

It is desired that the number-average molecular weight of PEI or itsderivatives is 300 to 500000, preferably 300 to 300000, more preferably500 to 100000.

Commercially available products of PEI include, for instance, EPOMINSP-003, EPOMIN SP-006, EPOMIN SP-200, EPOMIN P-1000 [hereinabovemanufactured by NIPPON SHOKUBAI CO., LTD., trade name], Lupasol[manufactured by BASF, trade name], and the like.

In addition, the polymer having quaternary ammonium groups includes, forinstance, hydroxyethylcellulose-hydroxypropyltrimethylammonium chlorideether, hydroxyethylcellulose-dimethyldiallylammonium chloridecopolymers, guar gum-hydroxypropyltrimetylammonium chloride ether,cationized pullulan, dimethyldiallylammonium chloride-acrylamidecopolymers, vinylpyrrolidone diethylsulfate-N,N-dimethylaminoethylmethacrylate copolymers, dimethyldiallylammonium chloride homopolymers,dimethyldiallylammonium chloride-acrylic acid copolymers,acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymers,cationized silicone copolymers and the like. These cation polymers canbe used alone or in admixture of at least two kinds.

Commercially available products of thehydroxyethylcellulose-hydroxypropyltrimethylammonium chloride etherinclude, for instance, LEOGUARD G, LEOGUARD NGP, LEOGUARD KGP[hereinabove manufactured by LION CORPORATION, trade names], CATINALHC-10, CATINAL LC-100 [hereinabove manufactured by Toho ChemicalIndustry Co., Ltd., trade names], and the like. Commercially availableproducts of the hydroxyethylcellulose-dimethyldiallylammonium chloridecopolymers include, for instance, CELQUAT L-200, CELQUAT H-60[hereinabove manufactured by National Starch and Chemical Corp., tradenames], and the like. Commercially available products of the guargum-hydroxypropyltrimetylammonium chloride ether include, for instance,JAGUAR C-13-S, JAGUAR C-15-S [hereinabove manufactured by SellaniesStein Hall, trade names], and the like. Commercially available productsof the dimethyldiallylammonium chloride-acrylamide copolymers include,for instance, MERQUAT L-550 [manufactured by CALGON Corp., trade name],and the like. Commercially available products of the vinylpyrrolidonediethylsulfate-N,N-dimethylaminoethyl methacrylate copolymers include,for instance, H. C. Polymer 5 [manufactured by Osaka Organic ChemicalInd., Ltd., trade name, trade name], GAFQUAT 755N [manufactured by ISP,trade name], and the like. Commercially available products of thedimethyldiallylammonium chloride homopolymers include, for instance,MERQUAT 100 [manufactured by CALGON Corp., trade name], and the like.Commercially available products of the dimethyldiallylammoniumchloride-acrylic acid copolymers include, for instance, MERQUAT 280,MERQUAT 295 [hereinabove manufactured by CALGON Corp., trade names], andthe like. Commercially available products of the acrylamide-acrylicacid-dimethyldiallylammonium chloride copolymers include, for instance,MERQUAT PLUS 3330 [manufactured by CALGON Corp., trade name], and thelike. Commercially available products of the cationized silicone polymerinclude SM8704C [manufactured by Toray-Dow Corning Silicone, trade name]and the like.

It is desired that the content of the cationic polymer in thepretreatment agent for a hair coloring with acid dye of this inventionis 0.01 to 30% by weight, preferably 0.05 to 20% by weight, from theviewpoints of effectiveness of coloring ability and color fastness,reducing squeakiness during rinsing and economics (when the cationicpolymer is added in an amount exceeding 30% by weight, the exceedingamount would be washed away by rinsing).

In addition, in the pretreatment agent for a hair coloring with acid dyeof this invention, urea can be contained as a component other than thecationic polymer in order to further improve coloring ability and colorfastness and reduce squeakiness during rinsing.

It is desired that the content of urea in the pretreatment agent for ahair coloring with acid dye of this invention is 0.1 to 60% by weight,preferably 0.5 to 40% by weight, from the viewpoints of effectiveness ofcoloring ability and color fastness, reducing squeakiness during rinsingand economics (when urea is added in an amount exceeding 60% by weight,the exceeding amount would be washed away by rinsing).

Also, in the present invention, it is preferable to use an organicsolvent in order to accelerate the penetration of the cationic polymerinto the hair.

The organic solvent includes, for instance, N-alkylpyrrolidones such as1-methyl-2-pyrrolidone and 1-ethyl-2-pyrrolidone; lower alkylenecarbonates such as ethylene carbonate and propylene carbonate; aromaticalcohols such as benzyl alcohol and 2-benzyloxyethanol; and the like.Furthermore, it is more preferable to use the above-mentioned aromaticalcohol in combination with the lower alcohol.

It is desired that the content of the organic solvent in thepretreatment agent for a hair coloring with acid dye of the presentinvention is 1 to 40% by weight, preferably 5 to 20% by weight, from theviewpoint of acceleration of satisfactory penetration of activeingredients into the hair. This is because when the content is less than1% by weight, the effect of acceleration of satisfactory penetration ofactive ingredients into the hair would be insufficient, and when thecontent exceeds 40% by weight, no further effects can be desired.

The balance of the above-mentioned components in the pretreatment agentfor a hair coloring with acid dye of this invention is water. As water,there can be used distilled water, tap water, purified water or thelike.

It is desired that pH of the pretreatment agent for a hair coloring withacid dye of this invention is 2 to 11, preferably 7 to 11. pH can beeasily adjusted by using a pH adjusting agent, including an organic acidsuch as citric acid, acetic acid, glycolic acid, levulinic acid ortartaric acid, phosphate buffer, ammonia, monoethanolamine, and thelike.

The formulation of the pretreatment agent for a hair coloring with aciddye of this invention is not limited to specified ones. Examples of theformulation include, for instance, aqueous solution, cream, gel,dispersion, emulsion, aerosol, and the like.

The pretreatment agent for a hair coloring with acid dye of thisinvention can be used as follows. First, hair is dipped in thepretreatment agent for a hair coloring with acid dye of this inventionat a temperature of room temperature to 60° C. for 1 minute to 1 hour,then washed with water, and thereafter dyed with a hair coloring withacid dye.

The hair coloring with acid dye is not limited to specified ones, andany of conventionally used ones can be used.

When the pretreatment agent for a hair coloring with acid dye of whichpH is adjusted to 7 to 11 is used, since hair becomes alkaline, it ispreferable to pre-treat the hair with a treatment agent so that the pHof the hair becomes around neutrality.

Furthermore, when the color of the colored hair with a hair coloringwith acid dye is changed or when the hair is further dyed with a haircoloring with acid dye, cation would be introduced into the hair by thepretreatment agent if the hair is previously subjected to decoloringtreatment with the pretreatment agent of this invention. Therefore,there are exhibited some excellent effects such that not only coloringability and color fastness are improved by the hair coloring with aciddye, but also squeakiness during shampoo-rinsing of the hair is reduced.Such excellent effects can be also exhibited for damaged hair.

Thus, when the removal of dye from colored hair is carried out using thepretreatment agent of this invention, the removal of dye from coloredhair can be effectively carried out. Furthermore, when the hair iscolored again with a hair coloring with acid dye after removing dye fromthe colored hair, there are exhibited some excellent effects such thatthe hair is excellent in coloring ability and color fastness and showsno squeakiness during rinsing, and feeling of the hair is adequatelymaintained. Such effects would be maintained without lowering even whenremoving dye from colored hair using the pretreatment agent and coloringwith the hair coloring with acid dye are repeatedly carried out.Therefore, coloring with the hair coloring with acid dye and removingdye from colored hair with the pretreatment agent can be repeatedlycarried out.

EXAMPLES

Next, this invention will be more specifically described on the basis ofthe following examples, without intending to limit this inventionthereto.

Examples 1 to 5 and Comparative Example 1

A component shown in Table 1 was diluted with distilled water so as tohave a concentration as shown in Table 1, to obtain a pretreatment agentfor a hair coloring with acid dye.

Coloring ability, color fastness and squeakiness were evaluated by thefollowing methods using the obtained pretreatment agent for a haircoloring with acid dye. The results are shown in Table 1.

[Coloring Ability]

One gram of a bundle of dried yak hair was dipped in the pretreatmentagent for a hair coloring with acid dye at room temperature for 15minutes (liquor ratio: 15 times), and washed in water for 1 minute.Thereafter, the moisture contained in the bundle was wiped off with aKIMTOWEL.

Next, the bundle of yak hair treated above was dipped in a 0.1% byweight aqueous solution of Orange 205 at room temperature for 20 minutes(liquor ratio: 15 times), washed in water for 1 minute and sufficientlydried, to obtain a colored bundle of hair.

The colored bundle thus obtained was directly measured using aspectrocolorimeter (manufactured by Nippon Denshoku Kogyo K.K., tradename: SZ-Σ80, hereinafter referred to the same), and a color difference(ΔE) between the colored bundle and the uncolored bundle was calculated.Thereafter, the coloring ability was evaluated.

It is indicated that the larger the ΔE is, the better the coloringability becomes.

[Color Fastness and Squeakiness]

Each bundle of colored hair was dipped in a 10% by weight aqueoussolution of EMAL 20C (sodium polyoxyethylene lauryl ethersulfate(3E.O.), manufactured by Kao Corporation, trade name) at 40° C.for 3 hours (liquor ratio: 15 times), washed in water for 1 minute, anddried at room temperature. The dried bundle of colored hair was measuredusing the spectrocolorimeter, and a color difference (ΔE) between thecolored bundle of hair and the uncolored bundle of hair was calculated.The color fastness was evaluated by comparing this color difference withthe color difference (ΔE) calculated when the coloring ability wasevaluated.

[Squeakiness when Washing Bundle of Hair with Water]

Five specialist panelists performed sensory evaluation on a decrease insqueakiness when the bundle of hair was washed in water on the basis ofthe following evaluation criteria.

(Evaluation Criteria)

⊚: Highly excellent (Four out of five evaluated as excellent).

∘: Excellent (Three out of five evaluated as excellent).

Δ: Slightly wrong (Two out of five evaluated as excellent).

X: Wrong (At most one out of five evaluated as excellent).

TABLE 1 Components of Pretreatment Agent Physical Properties for AcidicHair Dye Coloring Ability Color Fastness (% by weight) (ΔE) (ΔE)Squeakiness Ex. No. 1 CELQUAT L200*¹ (5) Distilled Water (95) 39.8 35.3◯ 2 H. C. Polymer 5*² (5) Distilled Water (95) 39.6 33.6 ◯ 3 MERQUAT100*³ (5) Distilled Water (95) 41.9 35.1 ◯ 4 SP-200*⁴ (5) DistilledWater (95) 42.6 32.4 ◯ 5 SP-006*⁵ (5) Distilled Water (95) 43.2 37.9 ◯Comp. Distilled Water (100) 38.7 28.2 X Ex. 1 (Note) *¹Hydroxyethylcellulose-dimethyldiallylammonium chloride copolymer (manufactured byNational Starch and Chemical Corp., trade name: CELQUAT L200, molecularweight: 100000 to 140000) *²Vinylpyrrolidonediethylsulfate-N,N-dimethylaminoethyl methacrylate copolymer (OsakaOrganic Chemical Ind., Ltd., trade name: H. C. Polymer 5, molecularweight: 200000 to 300000) *³Dimethyldiallylammonium chloride homopolymer(CALGON Corp., trade name: MERQUAT 100, molecular weight: 150000)*⁴Polyethyleneimine (number-average molecular weight: 10000,manufactured by NIPPON SHOKUBAI CO., LTD., trade name: SP-200)*⁵Polyethyleneimine (number-average molecular weight: 600, manufacturedby NIPPON SHOKUBAI CO., LTD., trade name: SP-006)

It can be seen from the results shown in Table 1 that the hair treatedwith a pretreatment agent for a hair coloring with acid dye containingthe polymer having amino groups or the polymer having quaternaryammonium groups (Examples 1 to 5) is more excellent in coloring abilityand color fastness than the hair treated with distilled water obtainedin Comparative Example 1.

Especially, it can be seen that coloring ability becomes more excellentwhen the hair is treated with the pretreatment agent for a hair coloringwith acid dye containing PEI.

Also, when the hair is treated with the pretreatment agents for a haircoloring with acid dye obtained in Examples 1 to 5, it can be seen thatthere is no squeakiness during shampoo-rinsing, so that smooth hairtreatment can be carried out.

Examples 6 to 9 and Comparative Example 2

PEIs having various molecular weights as shown in Table 2 were dilutedwith distilled water so as to have a concentration as shown in Table 2,to obtain a pretreatment agent for a hair coloring with acid dye.

Next, coloring ability was evaluated by the following method using theobtained pretreatment agent for a hair coloring with acid dye. Theresults are shown in Table 2.

[Coloring Ability]

One gram of a bundle of dried yak hair was dipped in the pretreatmentagent for a hair coloring with acid dye at room temperature for 20minutes (liquor ratio: 15 times), and washed in water for 1 minute.Thereafter, the moisture contained in the bundle was wiped off with aKIMTOWEL.

Next, the bundle of yak hair treated above was dipped in a 0.1% byweight aqueous solution of Orange 205 (containing 4% by weight citricacid) at room temperature for 20 minutes (liquor ratio: 15 times),washed in water for 1 minute and sufficiently dried, to obtain a coloredbundle of hair.

The colored bundle of hair thus obtained was directly measured using thespectrocolorimeter. The coloring ability was evaluated by calculating acolor difference (ΔE) between the colored bundle of hair and theuncolored bundle of hair.

It is indicated that the larger the ΔE is, the better the coloringability becomes.

TABLE 2 Physical Properties Components of Pretreatment Agent for AcidicHair Dye Coloring Ability (% by weight) (ΔE) Ex. No. 6 PEI[Number-Average Molecular Weight: 600] (10) MP(5) Distilled Water (85)46.9 7 PEI [Number-Average Molecular Weight: 1800] (10) MP(5) DistilledWater (85) 45.8 8 PEI [Number-Average Molecular Weight: 10000] (10)MP(5) Distilled Water (85) 48.3 9 PEI [Number-Average Molecular Weight:70000] (10) MP(5) Distilled Water (85) 46.8 Comp. — MP(5) DistilledWater (95) 43.4 Ex. 2

It can be seen from the results shown in Table 2 that the hair treatedwith a pretreatment agent for a hair coloring with acid dye containingPEI having a number-average molecular weight of 600 to 70000 (Examples 6to 9) is more excellent in coloring ability than the hair treated withdistilled water obtained in Comparative Example 2.

Examples 10 to 20 and Comparative Examples 3 and 4

PEI, urea and 1-methyl-2-pyrrolidone were dissolved in distilled waterso as to have the contents as shown in Table 3, to obtain a pretreatmentagent for a hair coloring with acid dye.

Next, coloring ability, color fastness and squeakiness were evaluatedusing the obtained pretreatment agent for a hair coloring with acid dye.The results are shown in Table 3.

Coloring ability was evaluated in accordance with the following method,and color fastness and squeakiness were evaluated in the same way as inExamples 1 to 5.

[Coloring Ability]

One gram of a bundle of dried yak hair was dipped in the pretreatmentagent for a hair coloring with acid dye at 50° C. for 15 minutes (liquorratio: 15 times), and washed in water for 1 minute. Thereafter, themoisture contained in the bundle was wiped off with a KIMTOWEL.

Next, the bundle of yak hair treated above was dipped in a 0.1% byweight aqueous solution of Orange 205 (containing 4% by weight citricacid) at room temperature for 20 minutes (liquor ratio: 15 times),washed in water for 1 minute and sufficiently dried, to obtain a coloredbundle of hair.

The colored bundle thus obtained was directly measured using thespectrocolorimeter, and a color difference (ΔE) between the coloredbundle of hair and the uncolored bundle of hair is calculated.Thereafter, the coloring ability was evaluated.

It is indicated that the larger the ΔE is, the better the coloringability becomes.

TABLE 3 Components of Pretreatment Agent for Acidic Hair Dye (% byweight) Physical Properties Distilled Coloring Ability Color FastnessSP-006 Urea MP Water (ΔE) (ΔE) Squeakiness Ex. No. 10 0.10 0 5 94.9 44.438.0 ◯ 11 1.25 0 5  93.75 44.3 37.0 ◯ 12 2.50 0 5 92.5 44.9 38.5 ◯ 135.00 0 5 90.0 44.6 39.8 ◯ 14 10.0 0 5 85.0 44.9 38.5 ◯ 15 20.0 0 5 75.043.5 39.3 ◯ 16 10.0 0.5 5 84.5 44.7 40.4 ⊚ 17 10.0 5.0 5 80.0 46.7 43.3⊚ 18 10.0 10.0 5 75.0 44.4 40.4 ⊚ 19 10.0 20.0 5 65.0 44.8 41.6 ⊚ 2010.0 40.0 5 45.0 46.3 42.9 ⊚ Comp. Ex. 3 0 0 5 95.0 40.9 33.8 X 4 0 20.05 75.0 41.9 35.0 X (Note) SP-006: Polyethyleneimine (manufactured byNIPPON SHOKUBAI CO., LTD., trade name, molecular weight: 600) MP:1-Methyl-2-pyrrolidone

It can be seen from the results shown in Table 3 that the hair treatedwith a pretreatment agent for a hair coloring with acid dye containing0.10 to 20% by weight of PEI (Examples 10 to 20) is more excellent incoloring ability and color fastness than the hair treated with apretreatment agent obtained in Comparative Example 3, in which PEI isnot used.

Also, it can be seen that the pretreatment agents for a hair coloringwith acid dye containing urea (Examples 16 to 20) are more excellent incolor fastness than the pretreatment agent for a hair coloring with aciddye not containing PEI (Example 14), and do not show squeakiness duringrinsing.

In addition, it can be seen from the comparison of Example 19 withExample 14 and Comparative Example 4 that the combined use of PEI andurea more improves coloring ability and color fastness as synergisticeffects than the single use of PEI or the single use of urea.

Examples 21 to 24 and Comparative Examples 5 and 6

PEI, urea and 1-methyl-2-pyrrolidone were dissolved in distilled waterso as to have a content as shown in Table 4, to obtain a pretreatmentagent for a hair coloring with acid dye.

Next, coloring ability, color fastness and squeakiness were evaluatedusing the obtained pretreatment agent for a hair coloring with acid dye.The results are shown in Table 4.

Coloring ability was evaluated in accordance with the following method,and color fastness and squeakiness were evaluated in the same way as inExamples 1 to 5.

[Coloring Ability]

One gram of a bundle of dried white human hair was dipped in thepretreatment agent for a hair coloring with acid dye at 50° C. for 15minutes (liquor ratio: 15 times), and washed in water for 1 minute.Thereafter, the moisture contained in the bundle was then wiped off witha KIMTOWEL.

Next, the bundle of white human hair treated above was dipped in a 0.1%by weight aqueous solution of Orange 205 (containing 4% by weight citricacid) at 50° C. for 20 minutes (liquor ratio: 15 times), washed in waterfor 1 minute and sufficiently dried, to obtain a colored bundle of hair.

The colored bundle thus obtained was directly measured using thespectrocolorimeter, and a color difference (ΔE) between the coloredbundle of hair and the uncolored bundle of hair is calculated.Thereafter, the coloring ability was evaluated.

It is indicated that the larger the ΔE is, the better the coloringability becomes.

TABLE 4 Pretreatment Agent for Acidic Hair Dye (% by weight) PhysicalProperties Distilled Coloring Ability Color Fastness SP-006 SP-200 UreaMP Water (ΔE) (ΔE) Squeakiness Ex. No. 21 10 — 0 5 85 52.0 48.3 ◯ 22 —10 0 5 85 54.2 50.6 ◯ 23 10 — 20 5 65 52.4 48.6 ⊚ 24 — 10 20 5 65 56.755.1 ⊚ Comp. Ex.  5  0  0 0 5 95 51.2 41.7 X  6  0  0 20 5 75 52.4 43.8X (Note) SP-006: Polyethyleneimine (manufactured by NIPPON SHOKUBAI CO.,LTD., trade name, molecular weight: 600) SP-200: Polyethyleneimine(manufactured by NIPPON SHOKUBAI CO., LTD., trade name, molecularweight: 10000) MP: 1-Methyl-2-pyrrolidone

It can be seen from the results shown in Table 4 that the pretreatmentagents for hair colorings with acid dye containing PEI (Examples 21 to24) are more excellent in coloring ability and color fastness than thepretreatment agent not containing PEI obtained in Comparative Example 5(FIG. 5) because the pretreatment agents for hair colorings with aciddye containing PEI accelerate the penetration of the dye.

Also, it can be seen that the pretreatment agents for a hair coloringwith acid dye in which PEI and urea are used together (Examples 23 and24, FIGS. 3 and 4) is more excellent in coloring ability and colorfastness and show no squeakiness during rinsing because the penetrationof the dye is more accelerated than the pretreatment agents for a haircoloring with acid dye in which PEI is singly used (Examples 21 and 22,FIGS. 1 and 2).

In addition, it can be seen that the pretreatment agent for a haircoloring with acid dye containing not PEI but urea obtained inComparative Example 6 (FIG. 6) does not so improve coloring ability andcolor fastness. To the contrary, the pretreatment agents for haircolorings with acid dye containing both urea and PEI obtained inExamples 23 and 24 are excellent in coloring ability and color fastnessand show no squeakiness during rinsing (FIGS. 3 and 4).

Examples 25 and 26 and Comparative Examples 7 to 9

PEI, QUARTAMIN 86W, urea and 1-methyl-2-pyrrolidone were dissolved indistilled water so as to have contents as shown in Table 5, to obtain apretreatment agent for a hair coloring with acid dye.

Next, coloring ability, color fastness and squeakiness were evaluatedusing the obtained pretreatment agent for a hair coloring with acid dye.The results are shown in Table 5.

Coloring ability was evaluated in accordance with the following method,and color fastness and squeakiness were evaluated in the same way as inExamples 1 to 5.

[Coloring Ability]

One gram of a bundle of dried white human hair was dipped in thepretreatment agent for a hair coloring with acid dye at 50° C. for 15minutes (liquor ratio: 15 times), and washed in water for 1 minute.Thereafter, the moisture contained in the bundle was wiped off with aKIMTOWEL.

Next, the bundle of white human hair treated above was dipped in a 0.1%by weight aqueous solution of Orange 205 (containing 4% by weight citricacid) at 50° C. for 20 minutes (liquor ratio: 15 times), washed in waterfor 1 minute and sufficiently dried, to obtain a colored bundle of hair.

The colored bundle thus obtained was directly measured using thespectrocolorimeter, and a color difference (ΔE) between the coloredbundle of hair and the uncolored bundle of hair is calculated.Thereafter, the coloring ability was evaluated.

It is indicated that the larger the ΔE is, the better the coloringability becomes.

TABLE 5 Pretreatment Agent for Acidic Hair Dye Physical Properties (% byweight) Coloring Color QUARTAMINE Distilled Ability Fastness P-1000 86WUrea MP Water (ΔE) (ΔE) Squeakiness Ex. No. 25 10 0 0 5 85 55.5 47.5 ◯26 10 0 20 5 65 54.3 53.1 ⊚ Comp. Ex.  7 0 0 0 5 95 52.8 42.1 X  8 0 5 05 90 56.9 51.6 X  9 0 5 20 5 70 55.6 51.7 X (Note) P-1000:Polyethyleneimine (manufactured by NIPPON SHOKUBAI CO., LTD., tradename, molecular weight: 70000) QUARTAMIN 86W: Stearyltrimethylammoniumchloride (manufactured by Kao Corporation, trade name, molecular weight:348.1) MP: 1-Methyl-2-pyrrolidone

It can be seen from the results shown in Table 5 that the pretreatmentagent for a hair coloring with acid dye containing PEI having amolecular weight of 70000 (Example 25, FIG. 7) is more excellent incoloring ability and color fastness than the pretreatment agent for ahair coloring with acid dye which does not contain PEI (ComparativeExample 7).

Also, it can be seen that the pretreatment agents for hair coloringswith acid dye containing stearyltrimethylammonium chloride (cationicsurfactant having a low molecular weight) in place of PEI (ComparativeExamples 8 and 9) somewhat improve coloring ability and color fastness,as compared to the pretreatment agent for a hair coloring with acid dyecontaining PEI having a molecular weight of 70000 (Example 25). However,the pretreatment agents show squeakiness.

In addition, it can be seen that the pretreatment agent for a haircoloring with acid dye containing PEI having a molecular weight of 70000and urea (Example 26, FIG. 8) is more excellent in color fastness andsqueakiness than the pretreatment agent for a hair coloring with aciddye containing only stearyltrimethylammonium chloride (cationicsurfactant having a low molecular weight) (Comparative Example 8).

Examples 27 to 30 and Comparative Examples 10 to 13

PEI, QUARTAMIN 86W, urea and 1-methyl-2-pyrrolidone were dissolved indistilled water so as to have contents as shown in Table 6, to obtainpretreatment agents for a hair coloring with acid dye.

Next, coloring ability, color fastness and squeakiness were evaluatedusing the obtained pretreatment agents for hair colorings with acid dye.The results are shown in Table 6.

Coloring ability was evaluated in accordance with the following method,and color fastness and squeakiness were evaluated in the same way as inExamples 1 to 5.

[Coloring Ability]

One gram of a bundle of dried white human hair was subjected tobleaching treatment (6% aqueous hydrogen peroxide (pH 10.2), roomtemperature, 1 hr (liquor ratio: 1:50)) to previously obtain a bundle ofdamaged hair. One gram of the bundle of damaged hair was dipped in thepretreatment agent for a hair coloring with acid dye at 50° C. for 15minutes (liquor ratio: 15 times), and washed in water for 1 minute.Thereafter, the moisture contained in the bundle was wiped off with aKIMTOWEL.

Next, 5 g of a commercially available hair coloring with acid dye A wasapplied to the bundle and kept at 50° C. for 20 minutes, washed in waterfor 1 minute, and thereafter sufficiently dried, to obtain a coloredbundle of hair.

The obtained colored bundle was measured using the spectrocolorimeter,and a color difference (ΔE) between the colored bundle of hair and theuncolored bundle of hair was calculated. Thereafter, the coloringability was evaluated.

It is indicated that the larger the ΔE is, the better the coloringability becomes.

TABLE 6 Pretreatment Agent for Acidic Hair Dye Physical Properties (% byweight) Coloring Color Bleaching QUARTAMIN Distilled Ability FastnessTreatment SP-006 P-1000 86W Urea MP Water (ΔE) (ΔE) Squeakiness Ex. No.27 Not Used 10 0 0 20 5 65 52.1 48.5 ◯ 28 Used 10 0 0 20 5 65 62.1 58.2◯ 29 Not Used 0 10 0 20 5 65 55.4 48.2 ⊚ 30 Used 0 10 0 20 5 65 63.954.5 ⊚ Comp. Ex. 10 Not Used 0 0 0  0 0  0 48.4 43.2 X 11 Used 0 0 0  00  0 57.3 50   X 12 Not Used 0 0 20 20 5 65 48.6 45.4 X 13 Used 0 0 2020 5 65 53.3 49.3 X

It can be seen from the results shown in Table 6 that the case where thetreatment is carried out using the pretreatment agent for a haircoloring with acid dye containing PEI and urea (Examples 27 and 29)gives more excellent coloring ability and color fastness than the casewhere the treatment is carried out without pretreatment (ComparativeExample 10) and shows no squeakiness during rinsing virgin hair.

The case where the treatment is carried out using the pretreatment agentfor a hair coloring with acid dye containing PEI and urea (Examples 28and 30) gives more excellent coloring ability than the case where thetreatment is carried out without pretreatment (Comparative Example 11),and gives no squeakiness to damaged hair (subjected to bleachingtreatment). Especially, the case where the treatment is carried outusing the pretreatment agent for a hair coloring with acid dyecontaining PEI having a low molecular weight and urea (Example 30) givesmore excellent color fastness to damaged hair than the case where thetreatment is carried out without pretreatment (Comparative Example 11).

Also, it can be seen that the case where the treatment is carried outwith the pretreatment agent for a hair coloring with acid dye containingstearyltrimethylammonium chloride and urea in place of PEI (ComparativeExample 12) gives coloring ability and color fastness for virgin hairwhich are not so different from the case where the treatment is carriedout without pretreatment (Comparative Example 10), and does not improvesqueakiness during rinsing.

In addition, it can be seen that the case where the treatment is carriedout using the pretreatment agent for a hair coloring with acid dyecontaining stearyltrimethylammonium chloride and urea in place of PEI(Comparative Example 13) gives coloring ability and color fastness fordamaged hair worse than the case where the treatment is carried outwithout pretreatment (Comparative Example 11), and does not improvesqueakiness during rinsing.

Example 31 and Comparative Example 14 and Reference Example 1

PEI (SP-003), urea and MP were dissolved in distilled water so as tohave contents as shown in Table 7, to obtain a pretreatment agent for ahair coloring with acid dye.

As the physical properties for the obtained pretreatment agent, feeling,decoloring ability, coloring ability, color fastness and squeakiness(squeakiness during rinsing off the shampoo) were evaluated by thefollowing methods. The results are shown in Table 7.

[Feeling]

A bundle of colored hair was dipped in the pretreatment agent as shownin Table 7 at 50° C. for 20 minutes (liquor ratio: 15 times), washed inwater for 1 minute, and thereafter sufficiently dried. Sensoryevaluation of feeling was made by five specialist panelists on the basisof the following evaluation criteria:

(Evaluation Criteria)

-   ⊚: Highly excellent (Four or five out of five judged that feeling    was excellent).-   ∘: Excellent (Three out of five judged that feeling was excellent).-   Δ: Slightly poor (Two out of five judged that feeling was    excellent).-   X: Poor (Zero or one out of five judged that feeling was excellent).    [Decoloring Ability]

Two grams of a hair coloring with acid dye (manufactured by PIACELABOCORP., trade name: Hair Make Color RESHADE O30) was applied to 1 g ofdried white human hair, and the hair was kept at room temperature for 10minutes, thereafter washed in water for 1 minute and sufficiently dried,to obtain a bundle of colored hair.

Next, this bundle of colored hair was dipped in the pretreatment agentas shown in Table 7 at 50° C. for 20 minutes (liquor ratio: 15 times),washed in water for 1 minute and thereafter sufficiently dried to obtaina bundle of hair from which the dye was removed.

The color difference of the bundle of hair after removing dye (ΔE₁) andthe color difference of the bundle of hair before removing dye (ΔE₂)were measured using a spectrocolorimeter (manufactured by NipponDenshoku Kogyo K.K., trade name: SZ-Σ80, hereinafter referred to thesame). Decoloring ability was evaluated in accordance with the followingequation:[Decoloring Ability]=[Color difference of bundle of hair (ΔE ₂) beforeremoving dye]−[Color difference of the bundle of hair (ΔE ₁) afterremoving dye].

It is indicated that the larger the numerical value of decoloringability is, the more excellent the decoloring ability becomes.

In addition, for the reference, the color difference (ΔE₁) of a bundleof hair in which 1 g of dried white human hair before coloring, fromwhich the dye was not removed, is also shown in Table 7 (ReferenceExample 1).

[Coloring Ability]

Two grams of a hair coloring with acid dye (manufactured by PIACELABOCORP., trade name: Hair Make Color RESHADE O30) was applied to thebundle of hair from which the dye was removed as described above(Example 31 and Comparative Example 14) and the bundle of hair fromwhich the dye was not removed (Reference Example 1), and the hair waskept at 50° C. for 20 minutes. Thereafter, the hair was washed in waterfor 1 minute and sufficiently dried, to obtain a bundle of colored hair.

The color difference (ΔE₃) of the obtained colored bundle was measuredusing a spectrocolorimeter (manufactured by Nippon Denshoku Kogyo K.K.,trade name: SZ-Σ80, hereinafter referred to the same).

It is indicated the larger the color difference (ΔE₃) of the coloredbundle is, the more excellent the coloring ability becomes.

[Color Fastness]

As to Example 31 and Reference Example 1, the bundle of colored hairobtained in the term of [Coloring Ability] mentioned above was dipped ina 10% by weight aqueous solution of sodium polyoxyethylene(3E.O.) laurylether sulfate (manufactured by Kao Corporation, trade name: EMAL 20C) at40° C. for 3 hours (ratio of hair: solution=1:15).

This bundle of colored hair was washed in water for 1 minute, and driedat room temperature. Thereafter, the color difference (ΔE₄) of thebundle of hair after the above-mentioned treatment was obtained.

The smaller the difference between the color difference (ΔE₃) of thebundle of colored hair and the color difference (ΔE₄) of the bundle ofhair after the above-mentioned treatment is, the more excellent thecolor fastness is.

On the other hand, the dye has been eluted from the bundle of coloredhair into the treatment solution after the above-mentioned treatment.Accordingly, in order to examine the degree of elution of the dye, theelution of the dye (dye concentration eluted in the solution, absorbanceat a wavelength of 487 nm) of a solution prepared by diluting thetreatment solution 30 times. When the coloring ability of both bundlesof colored hair is on the same level, the smaller the degree of elutionof dye is, the more excellent the color fastness is.

[Squeakiness During Rinsing Off Shampoo with Water]

Five specialist panelists had examined squeakiness during rinsing thebundle of hair obtained in the item of [Coloring Ability] in Example 31and Reference Example 1 with water by using a treatment solution [10% byweight aqueous solution of sodium polyoxyethylene(number of moles ofoxyethylene added: 3) lauryl ether sulfate (manufactured by KaoCorporation, trade name: EMAL 20C)] on the basis of the followingevaluation criteria.

(Evaluation Criteria)

-   ⊚: Highly excellent (Four or five out of five evaluated that there    was no squeakiness).-   ∘: Excellent (Three out of five evaluated that there was no    squeakiness).-   Δ: Slightly wrong (Two out of five evaluated that there was no    squeakiness).-   X: Wrong (Zero or one out of five evaluated that there was no    squeakiness).

TABLE 7 Physical Properties Color Fastness Components of PretreatmentAgent Degree of (% by weight) Decoloring Ability Coloring ElutionDistilled Decoloring Ability Of Dye SP-003 Urea MP Water ΔE₂ ΔE₁ AbilityΔE₃ ΔE₄ (A₄₈₇₎ Feeling Squeakiness Ex. No. 10 20 5 65 34.88 2.61 32.2744.8 42.7 0.14 ⊚ ⊚ 31 Comp.  0  0 5 95 34.46 27.86 6.6 — — — X X Ex. 14Ref. — — — — — 2.6*¹ — 41.1 37.7 0.13 X X Ex. 1 (Note) *¹The value forthe bundle of hair not subjected to coloring and decoloring treatments.

It can be seen from the results shown in Table 7 that the hair treatedwith the pretreatment agent containing PEI (Example 31) is moreexcellent in decoloring ability and feeling than the hair treated thepretreatment agent which does not contain PEI (Comparative Example 14),and shows little squeakiness (squeakiness during rinsing shampoo).

Also, the hair being colored after the treatment with the pretreatmentagent containing PEI (Example 31) is more excellent in coloring abilityand color fastness than the hair not subjected to dye-eliminatingtreatment (Reference Example 1).

Prescription Example 1 Preparation of Gel-Type Pretreatment Agent forHair Coloring with Acid Dye

A gel-type pretreatment agent for a hair coloring with acid dye wasprepared by mixing the following ingredients.

(Ingredients) (% by weight) PEI 10 Urea 20 Benzyl Alcohol  5 Ethanol 20Xanthan Gum  1 Perfume Proper Amount Purified Water Bal.

Prescription Example 2 Preparation of Liquid-Type Pretreatment Agent forHair Coloring with Acid Dye

A liquid-type pretreatment agent for a hair coloring with acid dye wasprepared by mixing the following ingredients.

(Ingredients) (% by weight) PEI 10 Urea 20 Benzyl Alcohol  5 Ethanol 20Perfume Proper Amount Purified Water Bal.

Prescription Example 3 Preparation of Hair Cream-Type Pretreatment Agentfor Hair Coloring with Acid Dye

A hair cream-type pretreatment agent for a hair coloring with acid dyewas prepared by mixing the following ingredients.

(Ingredients) (% by weight) Liquid Paraffin 15 Vaseline 15 White Beeswax2 Anticorrosive Agent Proper Amount Perfume Proper Amount PEI 5 Urea 20Xanthan Gum 0.1 Polyoxyethylene Cured 3 Castor Oil Purified Water Bal.

INDUSTRIAL APPLICABILITY

The pretreatment agent for a hair coloring with acid dye of the presentinvention exhibits some effects such that the pretreatment agentimproves coloring ability and color fastness of a hair coloring withacid dye.

1. A method of coloring hair comprising: (a) pretreating hair with apretreatment agent comprising polyethyleneimine or a derivative thereofand urea, wherein the content of urea in the pretreating agent is 0.1 to60% by weight; and (b) coloring said pretreated hair with a compositioncomprising an acid dye.
 2. The method for hair coloring with acid dyeaccording to claim 1, wherein the content of the polyethyleneimine or ina derivative thereof is 0.01 to 30% by weight.
 3. The method for haircoloring with acid dye according to claim 1 or 2, wherein thenumber-average molecular weight of the polyethyleneimine or a derivativethereof is 300 to
 500000. 4. The method for hair coloring with acid dyeaccording to claim 1, further comprising a step of washing the hairafter the pretreating step and before the hair coloring step.